The invention relates to a locking-aid device for a lock of the type used for the lock of the boot lid of the vehicle series W 140 produced by Mercedes. A published description of the lock, with references to the actuation of the locking aid, can be taken from German Patent Document DE 3,935,804 C2. The pneumatic locking-aid drive described is a single acting spring-returned diaphragm-piston servomotor which is operated at an overpressure of approximately 2.5 hPa on account of the high locking forces which occur when the abutment locking wedge is being drawn out of its catch position into the locking position.
When the lock is being opened, for example by pressing in the associated lock cylinder manually, the known locking-aid drive is extended in response to a signal from a microswitch detecting the position of the rotary latch of the lock and, in the course of this stroke, lifts out by means of a mechanism the detent pawl which keeps the extendable abutment, in the form of a locking wedge having a closed locking lug, in the retracted locking position. A spring can thereupon, in principle, push the locking wedge into its extended catch position. The advantage of the chosen arrangement is that only a single drive has to be provided for the locking-aid and the release functions.
However, in view of this, the movement of the abutment into the catch position is possible only when the locking-aid drive itself has also been brought into its position of rest, that is to say the pressure prevailing in it first has to be reduced. For the purpose of noise reduction, the pressure is not reduced abruptly, but only in a throttled manner.
Moreover, a relatively long time is also taken up in building up in the locking-aid drive the pressure which is not per se required in this amount for releasing the detent pawl.
Overall, the assumption of the (extended) locking-wedge catch position, in which the locking aid is made available, can be appreciably delayed in relation to the opening of the lock. Normally, it is true that this can be accepted without difficulty. But if the boot lid is to be closed again immediately after an unintentional opening, said delay can in fact be quite troublesome.
The vehicles mentioned in the introduction also have arranged in them near the lock a further (pneumatic) auxiliary drive which is intended for extending and retracting a handle for the boot lid and which can be operated at a relatively low overpressure level of 0.6 hPa via a separate pneumatic (dual-pressure) system and is activated immediately with the opening of the lock, so that the vehicle user is offered a dirt-free handle for lifting the boot lid.
Likewise known from German Patent Document DE 3,939,768 A1 is a movable handle for a vehicle boot lid, which is coupled kinematically to a rotary latch of the lid lock via a pivoting linkage and which, in the release position of said rotary latch, can be pivoted out of its concealed position of rest when the lid is closed.
It is also known per se from U.S. Pat. No. 3,016,968 to lift out a detent pawl by means of a single-acting pneumatic (underpressure) drive, in order to make it possible, for the remote-controlled opening of a boot lid, to bring a rotary latch of the boot-lid lock into its release position, said rotary latch being under spring prestress and being held in the locking position by the detent pawl.
German Patent Document DE 3,512,645 A1 also describes a device for actuating a tailgate lock, in which a detent pawl for a rotary latch of a lock can be lifted out by means of an electromagnetic drive upon actuation of an electrical control switch.
An object of the invention is to design a locking-aid device of the relevant generic type, in such a way that a repeated activation of the locking-aid drive in quick succession is possible.
This object is achieved, according to the invention, by providing a locking-aid device for a lock, especially for a vehicle door lock or flap lock, which has an abutment movable to and fro between a catch position assumed automatically during the opening of the lock and a locking position, especially a locking wedge having a closed locking lug, for a movable lock latch, comprising:
a locking-aid drive which is movable out of a position of rest during the locking of the opened lock for the purpose of bringing the abutment out of the catch position into the locking position,
a detent pawl for fixing the abutment in its locking position after the return of the locking-aid drive uncouplable from the abutment into its position of rest, and
a drive device for automatically lifting out the detent pawl, during the opening of the lock, by means of an operative connection,
wherein the drive device for lifting out the detent pawl by means of the operative connection is actuable independently of the locking-aid drive remaining in the position of rest, whereby the abutment can be moved automatically into its catch position immediately whenever the lock is opened, without the activation of the locking-aid drive.
The detent pawl can now be lifted out, during the opening of the lock, independently of a movement of the locking-aid drive by means of an operative connection. The locking-aid drive thus now no longer has to be activated during the opening of the lock, with the effect of a reduction of wear.
It would be possible, in principle, to couple the abutment detent pawl mechanically in a suitable way to the lifting-out mechanism for the rotary-latch detent pawl, in such a way that the two can be lifted out simultaneously or at least shortly after one another in the course of a manual opening-release movement. However, this seems to involve a relatively high outlay in view of the fact that the rotary-latch lock and its abutment are fastened to different constructional parts moving relatively far away from one another, namely, for example, the boot-lid edge and boot-lid frame, so that a mechanical operative connection would have to be guided by way of the hinge side of the lid (Bowden pull) or at all events would have to be uncoupled mechanically during the opening of the lid.
The latter would be possible, for example, with a pressure-pin/pressure-plate connection or the like in the locking gap, whilst the movement of the lock cylinder, when it is being pressed in, could be transmitted not Only directly to the rotary-latch detent pawl, but also, in a branch, to the abutment detent pawl, if appropriate with a lead. A lead could be brought about by an idle stroke or by utilizing the peripheral travels of a pivoting lever which are dependent on the distance from the pivot axis.
In any event, in comparison with the known locking-aid device, actions on the construction of the existing structures would be necessary.
Presupposing a leading release of the abutment closure, during opening the lock would then behave as follows: The user presses in the associated lock cylinder or pulls a door handle. Via the mechanical operative connection, the abutment detent pawl is lifted out and the abutment jumps into its catch position. Now, before the actual lock is released, the door or lid opens a little way, into the position in which the locking aid can be activated during the closing operation. In the course of the further movement of the lock cylinder or door handle, the rotary-latch detent pawl is now lifted out, and the door or lid can be opened completely, if appropriate the mechanical coupling in the locking gap being separated.
If, in contrast to this, according to another embodiment, a further independent drive is employed directly for lifting out the detent pawl, a reliable remedy, which is simple in purely constructive terms and which can be implemented quickly, against the undesirable delay discussed in the introduction is presented. Under the conditions discussed above, it is possible to have recourse in a cost-effective way to equipment already present in the vehicle for the independent operation of the further drive, since the activation of the handle drive via another quick-reacting pneumatic system means that the hardware prerequisites are already largely installed. It is merely necessary to lay a branch line from the existing system to the detent-pawl lifting out drive, and if appropriate a vent valve is also additionally installed.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.